The present invention relates to a device which is attached to a patient's clothing, and can be opened to allow access to a control panel. More particularly, the present invention relates to a transcutaneous electrical nerve stimulation (TENS) device which is worn by a patient and which allows the patient to control treatment while storing information used to evaluate the effectiveness of the pain treatment.
Millions of people suffer daily from chronic pain. A variety of treatment programs have been developed to alleviate chronic pain. One such program is medicinal pain treatment. Medicinal pain treatments utilize pill or other drug-type forms. An alternative treatment program is transcutaneous electrical nerve stimulation (TENS). A TENS system sends controlled bursts of electrical impulses into muscles and nerves at particular surface points. A mild vibrating sensation is felt by the patient using the TENS system. The pulses induce the patient's nervous system to raise its own natural substances, which prevent pain signals from reaching the brain. A TENS device can be used by a patient numerous times throughout the day whenever a patient desires pain relief.
The various pain treatments have been successful in achieving both short term and long term pain relief. However, since the physiological and psychological aspects of chronic pain are not yet fully understood, validating the effectiveness of any one pain treatment has remained an elusive goal. The need for measuring the outcomes of pain treatment is becoming more apparent.
A clinical outcome measurement usually takes place in a carefully controlled environment in order to reduce the number of variables to a minimum. This type of study is very good at verifying the null hypothesis of the experiment, but the controlled nature of the study may influence the outcome, as this controlled environment may introduce a hidden bias into the experiment. Some of the clinical conditions, such as pain or psychological state of the patient, cannot be measured in objective terms. Pain is the most prevalent complaint of patients and the single most frequent reason a person visits a physician, yet measurement of pain relief, and therefore quantifying treatment effectiveness, poses significant difficulties.
Presently, there are several methods of measuring clinical pain available, such as comparison of the patient's pain with experimentally induced pain and measurement of drug dosage required to abate the pain. The most common method for measuring pain and validating the effectiveness of a pain treatment is the manual pain rating scale. The manual pain rating scale operates independently from the particular pain treatment being used. An example is a Visual Scale which consists of a straight line drawn on a piece of a paper, the ends of which define the extreme limits of the pain experienced. Two other common types of manual pain rating scales are the Verbal Descriptor Scale and the Numeric Pain Scale. The Verbal Descriptor Scale (VDS) consists of a series of adjectives which describe different levels of pain. Alternatively, a Numeric Pain Scale (NPS) uses a series of consecutive numbers (e.g. from 1 to 10) with the smallest number representing "no pain" and the largest number representing "worst pain imaginable".
There are basically two approaches for using manual pain rating scales, absolute and comparative. The absolute approach measures the severity of the pain at a particular point in time. The comparative approach provides a measurement of the change in pain over time. When the patient periodically visits the clinician, the manual pain rating scale test is administered. The clinician provides the manual pain rating scale to the patient who then rates the perceived pain level on the scale provided. The clinician then collects the completed manual pain rating scale for future reference and comparison with other test results.
The manual pain rating scale is devised simply to measure the magnitude or intensity of pain at an arbitrary point in time. The manual pain rating scale may be used in conjunction with a pain treatment in an attempt to gauge the effectiveness of that treatment. However, the manual pain rating scale has a number of inadequacies. First, the manual pain rating scale is used primarily for clinical purposes by a practiced clinician. The form is completed on the periodic occasion when a patient visits his or her clinician. Therefore, records are not kept each and every time the pain treatment is used, rendering any data taken skewed and of limited value. Second, the manual pain rating scale does not "record" the pain level before and after each pain treatment. Third, the manual pain rating scale does not take into account the level of pain treatment being administered. Finally, the manual pain rating scale does not have the ability to store the duration of a pain treatment session.
In addition, where the manual pain rating scale is used at home by the patient, other deficiencies are encountered. These include: (1) "cramming bias, i.e., do all the paperwork at once before the clinic visit, (2) bias from comparison of how the pain was scored in the past, (3) lost data sheets, (4) lack of convenience being a demotivation, (5) disincentive for a clinic to use the tool due to the huge data reduction work load of processing even a few patients, and (6) data errors generated in interpreting paper scales, computer entry errors, and loss of data.
The above-stated inadequacies of the manual pain rating scale greatly impede its ability to provide any meaningful feedback as to the effectiveness of the pain treatment being used. The level of pain being experienced by the patient should be measured before each and every use of the pain treatment to provide an accurate history of the patient. Similarly, the measure of change in pain level following each pain treatment session is required to accurately determine the effectiveness of the treatment. The intensity level of each pain treatment and the length of a pain treatment session are necessary to provide an adequate explanation of the overall effectiveness. Importantly, the pain and pain treatment related data should be stored to create, in effect, a diary documenting a patient's improvement and correlation of the improvement to the pain treatment employed. The manual pain rating scale simply does not have these capabilities.
A substantial need exists for a convenient system having the ability to measure and record a patient's pain level before and after each pain treatment session along with the intensity and length of the pain treatment session.